208p build thread (papz's PCBs)

[tarandfeathers]

2) Anyone have a part number for a good 3.5mm jack with a normal that could be used on the signal in, preferable all metal without the black plastic most have?
3.5mm work fine on the main outs on mine, but the switching isn't good and only works well with tinijax cables on mine. Since this will be used with external synths etc until I get a bigger Buchla addiction, figure I might as well switch it (will look later and post if I find a good one before someone suggests).

Switchcraft 35PM2A - you'd have a hard time telling it was not a Tinijax connector rather than 3.5mm from the front of the panel. Or in fact from the back of the panel!

[papz]

Thanks for the info, Daniel.

[thecivildefense]

you can only CV the CO waveshape mix via the program card - it's available on Papz's 208 toolbox http://www.portabellabz.be/toolbox.html

NICE! Haha that's what I mean by me probably posting questions too early into figuring this out (Only had a couple hours to play with it so far). I built the toolbox and I guess just assumed it was switching mod. Then I was making a sequence last night and really wishing I had that knob modulating.
So I'm set on that already:) Thanks!

[thecivildefense]

2) Anyone have a part number for a good 3.5mm jack with a normal that could be used on the signal in, preferable all metal without the black plastic most have?
3.5mm work fine on the main outs on mine, but the switching isn't good and only works well with tinijax cables on mine. Since this will be used with external synths etc until I get a bigger Buchla addiction, figure I might as well switch it (will look later and post if I find a good one before someone suggests).

Switchcraft 35PM2A - you'd have a hard time telling it was not a Tinijax connector rather than 3.5mm from the front of the panel. Or in fact from the back of the panel!

AMAZING! Thanks so much for the help! Seems like all parts now take 2 weeks plus in the US these days but slowly getting everything together:)

[thecivildefense]

So finally in the tail end of setup. I calibrated for 1v/oct since I want the ability to easily interface with other gear and had to change resistor values a bit to get it in the middle of the range for calibration. It seems like stock values on the card diagrams are for 2v/oct, papz values did great for 1.2 but on mine max trimming was about a step too low between the low and top range all the way up. I used the following values to get 1v/oct right in the middle (using the pa726s):

MO Card 6:
R5 68k
R58 470k

CO Card 7:
R14 39k
R44 180k

Might be different for other people but just for a starting point.

[papz]

Thanks, thecivildefense

The new revision of the PCBs will arrive this week and should be available from SAmodular next week.

[thecivildefense]

I'm noticing an issue with tuning stability and I'm wondering if this is normal or if it points to some other issue. Once I have the scaling set, it stays in tune for several octaves throughout a session just fine.

However, most times when I turn it on the next day, even after warming up, I usually need to tweak the front panel trimmers for the MO and CO a little bit to get the scaling back to be correct (like over two octaves, the C might be about 20 or 30 cents off a few octaves up). Does that happen normally?

It's not a big issue since it stays in tune really well in a given session once it's set, but it seems odd to have to adjust the next time I use it.

[papz]

I don't think it suggests an issue, a small rescaling of the panel trim is often needed for perfect tuning.
Warming up takes 10-15 minutes to fully stabilize.
It's good to check the pA726 t° voltage anyway, but if it stays in tune once scaled it sounds ok.

The LPG setting also slightly alters tuning as Djangosfire reported viewtopic.php?f=17&t=194531&start=850#p3456401

[thecivildefense]

Ok thanks. Seems normal then. It stays in tune well once scaled, even over hours of being on

[Laughing]

Hey everyone.

I bought a preview unit of the 208p some time ago, and I'm finally getting around to completing it (After finishing DDRM#259).

I wanted to ask about the 4 capacitors on the slider side of the mainboard (C4,5,6,7). I see that they're 15uF axial, 25VDC, but I have some tantalums right now that I'd rather use instead of waiting for an order of Aluminum electrolytics. However, they're rated at 20VDC.

I spent some time on the schematic trying to find them, but for the life of me I can't. Does anyone know where they are on the schematic, or has the knowledge to tell me I can still use these 20V caps?

Thanks!

[papz]

Hi
These caps are the +/-15V, +5V and +12V power rails filters.
20V is thus ok but higher operating voltage extends their lifespan.

[Laughing]

That definitely answers my question!

I think I'll hold off on them if they're power supply decouplers unless I absolutely can't find them at my friendly surplus store, to which case I'll buy some more and pop them in.

[LED-man]

Tantalum or tantalum/polymer mix should be the best here, otherwise users have to use a bigger capacity and low ESR electrolyte caps, or we need more stability caps on the cards.
From my POV, a rework of the complete power rails are needed at all, the workarounds to minimize the bleeds is not the best option.
But this is also a problem in other 208 clones too.

[papz]

Finally

There was some delay because of DHL so-called 'Express'.

I'm happy to introduce the revised 208p boards.

Available very soon from SAmodular.

[LED-man]

[weedywhizz]

NICE job

And if people wonder if there will be black panels available ..... YES - for sure. Brushed, anodized and silkscreened.
Black 218 PCBs have arrived as well and awaiting black 248 MARF panels for those who want a 208 + 248 combo.

Parts for full kits are packed up and ready to go once I received the other stuff. Will update the shop very soon.

[thecivildefense]

Nice job! The masking and labelling will make this a much quicker build.

[papz]

Thanks
Fingers crossed it won't sound less vintage.

[RadekTymecki]

Just a quick update on the full kits:

Parts are all sourced. Unfortunately Mouser is fighting with Covid so I'm still waiting for a bunch of parts.

1. All resistor bags are packed and labeled - for 10 kits. Every resistor value comes with at least 1 spare resistor so you will have enough values available where on-test-selection is needed.
2. All caps are packed and labeled - for 10 kits. Ceramics are all 5mm TDKs with 5mm LS
3. New old stock parts included: 5x LM301AN, 2x 2N3565, 2x 2N4339 (one selected), 2x 2N4340, 2x 2N4341, 1x DG200BA, 2x MC846P, 2x CA3046 for the pA726, 1x TE1140 390uF cap and 2x Excelitas VTL5C3/2. With a bit of luck I'll also have uA726 available.
4. No cheap chinese 56pin Edgecard connectors - 2 Sullins connectors will be included.

I'm also going to include cables for power wiring + shielded cable for the reverb tank. So this kit can be called a full kit for sure

The kits will be available once the new PCBs are in. A fresh - triple checked BOM comes with the kits. Including the pA726 BOM.

what will be the estimated price for full kit ?

[weedywhizz]

Just a quick update on the full kits:

Parts are all sourced. Unfortunately Mouser is fighting with Covid so I'm still waiting for a bunch of parts.

1. All resistor bags are packed and labeled - for 10 kits. Every resistor value comes with at least 1 spare resistor so you will have enough values available where on-test-selection is needed.
2. All caps are packed and labeled - for 10 kits. Ceramics are all 5mm TDKs with 5mm LS
3. New old stock parts included: 5x LM301AN, 2x 2N3565, 2x 2N4339 (one selected), 2x 2N4340, 2x 2N4341, 1x DG200BA, 2x MC846P, 2x CA3046 for the pA726, 1x TE1140 390uF cap and 2x Excelitas VTL5C3/2. With a bit of luck I'll also have uA726 available.
4. No cheap chinese 56pin Edgecard connectors - 2 Sullins connectors will be included.

I'm also going to include cables for power wiring + shielded cable for the reverb tank. So this kit can be called a full kit for sure

The kits will be available once the new PCBs are in. A fresh - triple checked BOM comes with the kits. Including the pA726 BOM.

what will be the estimated price for full kit ?

Will do final calculations this weekend. Somewhere between 1000 - 1200€ ex. VAT. Parts are all packed up - PCBs will arrive on Friday - panels on Friday or Monday.

[RadekTymecki]

Just a quick update on the full kits:

Parts are all sourced. Unfortunately Mouser is fighting with Covid so I'm still waiting for a bunch of parts.

1. All resistor bags are packed and labeled - for 10 kits. Every resistor value comes with at least 1 spare resistor so you will have enough values available where on-test-selection is needed.
2. All caps are packed and labeled - for 10 kits. Ceramics are all 5mm TDKs with 5mm LS
3. New old stock parts included: 5x LM301AN, 2x 2N3565, 2x 2N4339 (one selected), 2x 2N4340, 2x 2N4341, 1x DG200BA, 2x MC846P, 2x CA3046 for the pA726, 1x TE1140 390uF cap and 2x Excelitas VTL5C3/2. With a bit of luck I'll also have uA726 available.
4. No cheap chinese 56pin Edgecard connectors - 2 Sullins connectors will be included.

I'm also going to include cables for power wiring + shielded cable for the reverb tank. So this kit can be called a full kit for sure

The kits will be available once the new PCBs are in. A fresh - triple checked BOM comes with the kits. Including the pA726 BOM.

what will be the estimated price for full kit ?

Will do final calculations this weekend. Somewhere between 1000 - 1200€ ex. VAT. Parts are all packed up - PCBs will arrive on Friday - panels on Friday or Monday.

the price is nice! the pcb's are new revs from papz?

[papz]

Yes

[search64]

Great, broke another reverb tank.

Does anybody know what part number this two pin connector is:

[weedywhizz]

Product page @ samodular.com is mostly done. Added full kits and a fresh BOM. A fresh BOM is also up for Portabellabz 208 Toolbox.
If you prefer to have the BOM separated for the MB and cards - no problem - let me know.
Will do fresh pictures on Monday / Tuesday once the new silver and black panels are in. Current pictures are a bit older and show the previous revision of PCBs without reference designators and soldermask for example.

If you have have questions or suggestions what could be made better please let me know. Thanks you.
https://www.samodular.com/product/208-e ... s-bundles/


Cheers
Steffen